2D Low Level Mixing Bag For Storage And Shipping

ABSTRACT

A disposable container, such as a deformable bag, for a fluid, having one or more inlets and one or more outlets and an impeller assembly within the container to cause mixing, dispersing, homogenizing and/or circulation of one or more ingredients contained or added to the container. The region within the container that can contain liquid is funnel shaped, which allows very low fluid level mixing, dispensing while mixing, and a reduction or elimination of vortex formation.

This application claims priority of U.S. Provisional Application Ser.No. 61/731,129 filed Nov. 29, 2012, the disclosure of which isincorporated herein by reference.

FIELD

The embodiments disclosed herein relate to a disposable 2D container andimpeller assembly, the impeller assembly preferably being magneticallydriven and coupled to the container.

BACKGROUND

Traditionally, fluids have been processed in systems that utilizestainless steel containers. These containers are sterilized after use sothat they can be reused. The sterilization procedures are expensive andcumbersome as well as being ineffectual at times.

In order to provide greater flexibility in manufacturing and reduce thetime needed to effect a valid regeneration of the equipment,manufacturers have begun to utilize disposable sterilized bags that areused once with a product batch and then disposed.

An example of use of these disposable bags is in a system for mixing twoor more ingredients, at least one of which is liquid and the other(s)being liquid or solid and the bag has a means for causing theingredients to mix as uniformly as possible.

For example, in the production of vaccines, the liquids involved oftencontain aluminum salt as an adjuvant. The aluminum salt improves theeffectiveness of the vaccine by enhancing the body's immune response.Unfortunately, the aluminum salt has particles sizes larger than 0.2 μm,and thus sterile filtering generally is not an option. As a result, itis often advantageous to minimize the number of containers into whichthe vaccine needs to be transferred, since each transfer represents apotential breach of sterility, and the resulting contamination can't befiltered away. Accordingly, it is advantageous to be able to mixvaccines in the same container, such as a flexible, disposable bag, thatthey are shipped in.

Another example is a bioreactor or fermentor in which cells are eitherin suspension or on microcarriers and the bag has a means forcirculating the liquid, gases and in some cases the cells around theinterior of the bag.

Most conventional mixing bags are shaped like cylinders, with the bottomof the bag forming a cone, to mimic the shape of the tanks that thedisposable bags are replacing. Although this shape is conducive tomixing the contents of the bag, it is not conducive to shipping andstorage.

Other conventional mixing bags are shaped like cubes. The cube shape isconducive to shipping and storage, but is not a good shape for mixing,as the corners of the cube easily can become dead spots where mixing isimpeded.

Typically, the means for mixing or circulating is a magnetically coupledimpeller contained within the bag and a magnetic motor outside the bagwhich remotely causes the impeller to spin.

It therefore would be desirable to provide a disposable, preferablydeformable, container for fluids that is conducive to mixing, shippingand storage. It also would be desirable to form a flat, 2D bag made fromtwo pieces of film bonded together to form a funnel-shape and anintegral impeller assembly located towards the bottom of the funnel. Theflat nature of the bag is conducive to shipping and storage in an emptyor full state.

SUMMARY

In accordance with certain embodiments, disclosed herein is a disposablecontainer, such as a deformable bag, for a fluid, the container havingone or more inlets and one or more outlets and one or more impellerassemblies within the container to cause mixing, dispersing,homogenizing and/or circulation of one or more ingredients contained oradded to the container. In accordance with certain embodiments, theregion within the interior of the disposable container that can containliquid and in which liquid is introduced is delimited by liquidimpermeable seams sealingly adjoining walls of the container. Inaccordance with certain embodiments, the region within the interior ofthe disposable container that can contain liquid and into which liquidis introduced is angled in the shape of a funnel, where the small end ofthe funnel is proximate the outlet of the container.

Also disclosed is a system for mixing ingredients in a container, thesystem comprising a 2D container having a mixing region that is shapedto minimize or eliminate dead spot regions, one or more impellerassemblies, and one or more drives for the impeller assembly orassembly. In accordance with certain embodiments, the mixing region isdelimited by liquid impermeable seams sealingly adjoining walls of thecontainer. In accordance with certain embodiments, the mixing region isfunnel-shaped. In accordance with certain embodiments, an outlet of thecontainer is at the narrowest region of the funnel shape.

Also disclosed is a method of mixing ingredients in a disposablecontainer with one or more impeller assemblies disposed in thecontainer. The method includes introducing ingredients to be mixed intoa container, wherein one or more impeller assemblies is at leastpartially contained in and is sealed in the container, and driving theblades or vanes of the impeller assembly or assemblies to agitate theingredients in the bag. The ingredients occupy a shaped region in thebag that minimizes or eliminates dead spots. Preferably the shapedregion is funnel-shaped. In certain embodiments, the driver(s) for theimpeller assembly or assemblies is external to the bag, and the impellerassembly or assemblies is driven magnetically. In certain embodiments,at least one of the ingredients to be mixed is a liquid.

Also disclosed is a liquid processing system which comprises adisposable container having one or more inlets and one or more outletsand one or more impeller assemblies within the container to causemixing, dispersing, homogenizing and/or circulation of one or moreingredients contained or added to the container, and a tangential flowfiltration unit and conduits to effect flow from the container to thetangential flow filtration unit and back to the container. Theingredients occupy a shaped region in the bag that minimizes oreliminates dead spots. Preferably the shaped region is funnel-shaped.

The funnel shape directs any settling solids back to the impellerassembly, where they are re-agitated. The funnel-shape also improvesdrainability out of the container.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a disposable container in accordance withcertain embodiments;

FIG. 2 is a photograph of a filled disposable container being mixed inaccordance with certain embodiments;

FIG. 3 is a top view of a mixing element in accordance with certainembodiments;

FIG. 4 is a cross sectional view of the mixing element taken along lineA--A of FIG. 3; and

FIG. 5 is a schematic view of a disposable container in accordance withan alternative embodiment.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

In accordance with certain embodiments, the disposable containerdesigned to receive and hold ingredients can be formed of monolayer ormultilayer flexible walls formed of a polymeric composition such aspolyethylene, including ultrahigh molecular weight polyethylene, linearlow density polyethylene, low density or medium density polyethylene;polyproplylene; ethylene vinyl acetate (EVOH); polyvinyl chloride (PVC);polyvinyl acetate (PVA); ethylene vinyl acetate copolymers (EVAcopolymers); blends of various thermoplastics; co-extrusions ofdifferent thermoplastics; multilayered laminates of differentthermoplastics; or the like. By “different” it is meant to includedifferent polymer types such as polyethylene layers with one or morelayers of EVOH as well as the same polymer type but of differentcharacteristics such as molecular weight, linear or branched polymer,fillers and the like. Typically medical grade and preferably animal-freeplastics are used. They generally are sterilizable such as by steam,ethylene oxide or radiation such as beta or gamma radiation. Most havegood tensile strength, low gas transfer and are either transparent or atleast translucent. Preferably the material is weldable and isunsupported. Preferably the material is clear or translucent, allowingvisual monitoring of the contents. The container can be provided withone or more inlets, one or more outlets and one or more optional ventpassages. One or more impeller assemblies can be positioned in thecontainer for mixing the container contents.

In certain embodiments, the container may be a disposable, deformable,foldable bag that defines a volume, that is sterilizable for single use,capable of accommodating contents, such as biopharmaceutical liquids,and that can accommodate one or more mixing devices partially orcompletely within the interior of the container. The volume can be aclosed volume that can be opened, such as by suitable valving, tointroduce a liquid into the volume, and to dispense liquid therefrom,such as after mixing is complete.

The container is preferably a two dimensional (2D) or “pillow” bag,formed by joining two or more sheets of material (or a single sheet toitself) in sealing relation. Preferably it is a single-use container.

In accordance with certain embodiments, portions of the container can besealed such as by welding to create regions where no liquid is presentand where no liquid can flow, thereby modifying the shape of the volumeof the container that receives liquid to be mixed. An example is shownin FIG. 1, where a funnel-shaped container is formed from initiallyrectangular sheets of material. Those skilled in the art will appreciatethat other initial material shapes can be used to form the final desiredfunnel-shape. The lower left and right corner triangular regions 38, 39of the container 10 are sealed and are not in fluid communication withan inlet 12 or outlet 14, and therefore contain no ingredients to bemixed. Similarly, optionally upper left and right corner triangularregions 40, 41 of the container are sealed and are not in fluidcommunication with an inlet or outlet, and therefore contain noingredients to be mixed.

More specifically, in accordance with certain embodiments, region 38,which is sealed from and not in fluid communication with mixing region50, is defined by the container sealed end walls 38 a, 38 b, and byinterior sealed wall 38 c. Region 39, which is sealed from and not influid communication with mixing region 50, is defined by the containersealed end walls 39 a, 39 b, and by interior sealed wall 39 c. Interiorsealed wall 38 c is angled, such as about a 45° angle, relative to endwall 38 a and end wall 38 b. Interior sealed wall 39 c is angled, suchas about a 45° angle, relative to end wall 38 a and end wall 38 b. Otherangles, such as angles from about 22.5° to about 60°, also areacceptable. These two walls thus create a region 50 that is taperedtoward the outlet 12.

Optionally region 40, which is sealed from and not in fluidcommunication with mixing region 50, is defined by the container sealedend walls 40 a, 40 b, and by interior sealed wall 40 c. Optionallyregion 41, which is sealed from and not in fluid communication withmixing region 50, is defined by the container sealed end walls 41 a, 41b, and by interior sealed wall 41 c.

The sealing of walls can be carried out by welding using heat to meltand fuse or bond the material as is known in the art. Alternatively, thebag could be blow molded or the walls could be adhered together with anadhesive.

Accordingly, ingredients introduced into the container can occupy onlythe mixing volume 50 defined by container sealed walls 38 c and 39 c(and optionally sealed walls 40 c and 40 d), and container end walls 10a (between end wall 40 a and 38 a), 10 b (between end wall 39 a and 41a), 10 c (between end wall 41 b and 41 b), and 10 d (between end wall 38b and 39 b).

In view of the shape of the region 50, the introduction of fluid intothe region 50 causes the container 10 to expand to an elliptical shapedcross-section. This closely mimics a 3D bag.

In accordance with certain embodiments, the sheet or sheets used to formthe container can initially be shaped in a funnel-shape, as shown inFIG. 5, such as by cutting rectangular sheets to form a funnel shape.The perimeter walls of the funnel-shaped sheets (e.g., 38 c′ and 39 c′)can then be sealed to one another to form the funnel-shaped 2D bag. Inthe embodiment shown in FIG. 5, the upper left region 40 and upper rightregion 41 are formed as in the embodiment of FIG. 1, although thesecould also be pre-cut in the desired shape, thereby eliminating theregions 40 and 41. A hard bottomed (funnel) bag with a flexible wallalso could be used.

The container 10 contains, either partially or completely within itsinterior, one or more impeller assemblies 60 for mixing or circulatingthe ingredients contained in the mixing region 50 of the container 10.The impeller assembly can be made of a suitable plastic material, suchas polyethylene, that does not react or otherwise interfere with theintended liquid contents of the container. In accordance with certainembodiments, each impeller assembly includes one or more blades, whichare movable, such as by rotation or oscillation about an axis. Thenumber and shape of the blades is not particularly limited, providedthey provide sufficient agitation of the fluid within the container whenactuated. The blade or blades may also be constructed of plasticmaterial, such as polyethylene, or any polymer resistant to gammairradiation, such as a polypropylene co-polymer. In certain embodiments,the impeller assembly 60 converts rotational motion into a force thatmixes the fluids it is in contact with. Preferably an impeller assembly60 is located in proximity to the bottom of the container, preferablycentrally located with respect to the longitudinal centerline of thecontainer 10. Placing the impeller assembly 60 near the bottom of thefunnel shape allows for mixing even at very low liquid levels in thecontainer 10, and allows for mixing to continue during dispensing.Preferably the impeller assembly is as close to the bottom of thecontainer as possible, limited by the size of the impeller assembly.Having it as close to the bottom of the container as possible allows theimpeller to keep mixing for as long as possible until the fluid level isbroken by the rotating blades. The resulting container can mix 1/10 ofits full volume, and have its impeller remain completely submerged inthe process liquid. This allows mixing at low liquid levels withoutsplashing or foam generation, ensures complete drainability, and allowsthe bag to actively mix while dispensing, even at a very low (about 1/10the capacity of the bag) levels of liquid in the bag.

In certain embodiments, the impeller assembly 60 has a magnetic base,such as a mixing impeller overmolded magnet. In certain embodiments,when the impeller assembly 60 is installed in the container 10, themagnetic base protrudes outside the container 10, with the remainder ofthe impeller assembly 60 is housed inside the container 10. The driver62 (e.g., a magnetic driver) for the impeller assembly is external tothe container 10.

In accordance with certain embodiments, the impeller assembly 60 has aprotective hood 18 surrounding at least a portion of the moveable bladesor vanes 16 of the impeller assembly and being above at least a portionof the blades or vanes 16, as shown in FIGS. 3 and 4. In accordance withcertain embodiments, the hood 18 surrounds the blades or vanes 16 andarcs over the height of the blades or vanes. Even more particularly, incertain embodiments the hood 18 is shaped in a dome shape orsemi-spherical shape that is around and above the impeller blades. Thehood 18 has one or more, preferably, two or more openings to allow forgood liquid circulation when the blades are in motion. The hood acts asa protector for the container surface against the impeller assembly bothduring shipping and storage as well as when in use, particularly atlower liquid levels. In addition, the hood can, in some embodiments, actas a vortex breaker especially at lower liquid levels so as to preventfoaming and to increase turbulence and therefore mixing efficiency.

In certain embodiments, the protective hood 18 is coupled to the basewith one or more ribs or legs 19. Where a plurality of ribs 19 is used,preferably they are equally spaced. The open regions between spaced ribs19 are generally normal to the axis about which the impeller bladesrotate, and provide fluid access to the interior of the impellerassembly. The number and shape of the blades is not particularlylimited, provided they provide sufficient agitation of the fluid withinthe container when actuated. The base 14 and hood 18 define a housingfor the moveable blade or blades, and can be made of a suitable plasticmaterial such as polyethylene, that does not react or otherwiseinterfere with the intended liquid contents of the container. The bladeor blades may also be constructed of plastic material, such aspolyethylene, or any polymer resistant to gamma irradiation, such as apolypropylene co-polymer.

The top surface of the hood 18 should be smooth to avoid damaging thecontainer upon contact with the hood. In certain embodiments, the topsurface of the hood 18 includes a plurality of spaced apertures 26formed therein, to allow fluid passage to and from the interior of theimpeller assembly 60. In the embodiment shown in FIG. 3, a first ring ofspaced apertures is located near the outer circumferential edge of thetop surface, a second ring of spaced apertures is located radiallyinwardly of the first ring, and a third ring of apertures is locatedradially inwardly of the second ring. In the embodiment shown in FIG. 3,the first ring of spaced apertures includes twelve apertures; the secondring of spaced apertures includes twelve apertures, and the third ringof spaced apertures includes six apertures. Those skilled in the artwill appreciate that the particular number and pattern of apertures isnot limited to the embodiment shown in FIG. 3. Although in theembodiment shown, each aperture within a ring is equally sized and isgenerally circular, the shape and diameter of the apertures is notlimited. The apertures can be formed by a variety of means, such as bydrilling.

Preferably the hood is dome shaped to protect the container, and theassembly has side openings to pull liquid in, and openings in the hoodto propel liquid out. In general, the amount of open area in the hood isa trade-off between the ability of the hood to protect the bag fromdamage, and the mixing efficiency of the impeller assembly. For the unitto work efficiently, it needs to be able to pull fluid in from the sideopenings in the hood (i.e. the spaces between the legs). It also needsto be able to propel the fluid out through the top (hence the need forthe apertures in the hood). The more open area on top, the better themixing efficiency. However, if the size of the apertures is too large,the container material could sag through them and touch the impeller,damaging the container.

The container 10 may contain one or more inlets 12 and outlets 14 andoptionally other features such as sterile gas vents (not shown) andports (not shown) for the sensing of the liquid within the container forparameters such as conductivity, pH, temperature, dissolved gases andthe like. Those skilled in the art will appreciate that although element12 is labeled an inlet and element 14 is labeled an outlet, these couldbe reversed so that element 12 is the outlet and element 14 is theinlet, or they each could function as both inlets and outlets.

In one embodiment, the disposable container is positioned within a solidsupport container for ease of filling and emptying the container offluid.

FIG. 2 illustrates the elliptical shape of the container 10 when filled,and shows the external magnetic motor drive 62 and the impeller assembly60 positioned at an angle “X” relative to the longitudinal centerline ofthe container 10. The angle of the impeller assembly causes a linenormal to the impeller assembly to be directed to the opposite face ofthe container 10, which reduces or eliminates the formation of a vortex,and increases turbulence and mixing efficiency. This is particularlydesirable when processing shear or oxygen-sensitive proteins.

What is claimed is:
 1. A disposable container for a fluid whichcomprises: a volume formed of a flexible material, one or more inlets insaid container, one or more outlets in said container, an impellerassembly mounted at least partially within said closed volume of saidcontainer, wherein said volume is formed in a funnel shape.
 2. Thedisposable container of claim 1, wherein said impeller assembly ismagnetically driven.
 3. The disposable container of claim 1, whereinsaid container has a bottom having one of said outlets, and wherein saidfunnel shape narrows towards said one of said outlets.
 4. The disposablecontainer of claim 3, wherein said impeller assembly is mounted nearsaid one of said outlets.
 5. A method of mixing ingredients in adisposable container having one or more impeller assemblies, comprisingintroducing said ingredients to be mixed into said container, drivingsaid impeller assembly to agitate said ingredients, wherein saidingredients occupy a shaped region in the bag that minimizes oreliminates dead spots, said shaped region comprising a funnel-shape. 6.The method of claim 5, wherein said container has a bottom having anoutlet, and wherein said funnel shape narrows towards said outlet. 7.The method of claim 6, wherein said impeller assembly is mounted nearsaid outlet.